In his Tokyo hotel room after his knockout loss to Wanderlei Silva, Brian Stann made up his mind. He was done fighting, he told his coaches that night. He’d had enough.

“I was frustrated at the time,” Stann told MMAjunkie.com (mmajunkie.com). “I’d put so much of my heart and soul into fighting and made sacrifices in other areas of my life, and it no longer felt worth it to me.”

Of course, this was right after a loss. Fighters say a lot of things after a loss, and they don’t always still mean them all in the morning. But this was different, and Stann knew it right away. He also knew, just from watching some of his contemporaries go back and forth on the issue, that he should wait a while before he said anything publicly. He told his wife. He told his mother. Other than that, he kept it quiet.

“I didn’t want to be one of the guys that made the announcement and then went back on it and ended up looking unprofessional,” Stann said. “So I’ve given it a lot of time, but I was very sure.”

And so that’s it for Brian Stann the fighter. Seven years as a pro, a 12-6 career record and brief stint with the now non-existent WEC light heavyweight title. You can put it on his MMA tombstone, because he’s calling it quits at 32. The inevitable question is why. As usual with such big, complicated questions, there are a number of answers, but let’s start with the one between his ears.

As anyone who knows him well tell you, Stann’s smart enough to understand that you only get one brain in this life, and you may have to live with what you do to it for a long time. With two young daughters, aged 3 and 5, and another on the way this fall, those concerns weigh heavier on him now than they once did.

“I played football for a long time, and then I went to Iraq, and then I fought for eight years,” said Stann, who played linebacker at the U.S. Naval Academy before being deployed to Iraq in 2005, where he would later receive the Silver Star for his service as a U.S. Marine. “You can’t be a father of three children and not pay attention to some of things that go on with athletes who get hit a lot. This CTE [Chronic Traumatic Encephalopathy] stuff is very serious. There’s no way I can get an MRI or a CT scan and see what’s going on with that right now. I’ve been banging my head around for a substantial part of my life. I don’t think I’ve felt any real effects of that, but it’s not something I’m willing to risk. I’m about to have my third child sometime this fall, and my No. 1 job in life is being a husband and father. There’s nothing that comes remotely close to that.”

This is more or less exactly what Stann said he told UFC President Dana White when he broke the news recently that he wouldn’t be taking any more fights in the UFC.

“He was extremely supportive,” Stann said. “And I told him, ‘I’ve been hit in the head a long time and I don’t have any issues, but the time to stop is not when you start having the issues.’ That’s something that resonated with him immediately. He didn’t try to talk me out of it at all.”

It helps that Stann has options. He’s reportedly become a favorite of the FOX network for his work as a commentator on UFC broadcasts, and he just signed a deal to join the FOX Sports South broadcast team for ACC college football games this fall. Away from the camera, he’s the president and CEO of Hire Heroes, a not-for-profit organization that specializes in helping returning military veterans find jobs as civilians.

But even without those other jobs to fall back on, Stann said, he would have called it quits after the Silva loss regardless. It’s not just the potential damage to his brain from “Fight of the Night”-worthy brawls like that one, either. It’s also because he knows what he’d have to do in order to have any shot at being a contender again. For starters, he’d have to spend at least a couple months before each fight training at Greg Jackson’s gym in Albuquerque, N.M. If he stayed home in Atlanta, where his wife and daughters are, he simply wouldn’t get the training he needs, he said.

“In Atlanta, I’m the leader in that room,” Stann said. “And that’s fine, I like doing that. A lot of the guys who I train with there have had great success, but I haven’t. … In order for me to fight at a high level, which I have not been able to do as of late, I would have to make changes that would really be to the detriment of my wife and kids. I’m just simply no longer willing to do that at this point.”

Besides, Stann said, even if he were to make those sacrifices and put that game face on again, he’s still facing a long climb. He’s lost two in a row in the UFC, and three of his past four. He has no desire to stick around just for the sake of fun fights and the occasional bonus check. If he’s not on his way to fighting for a title, he said, he’s not interested.

“If I’d won that [Silva] fight, it’s one of those things where, yeah, you’re going to want to keep going,” Stann said. “It takes a loss to put things in perspective. Specifically, that loss knocked me down the ladder. I had worked my up to a certain level, was Top 10 for two years, and was on the cusp of a title shot, which is also being on the cusp of making really great long-term money. The UFC has given me those opportunities, and look, I’ve lost them all. That fight was another one of those opportunities. You don’t get that many as a fighter. The more time you dedicate to doing that, the less time you spend developing the skills that are going to help you the rest of your life.”

It’s not easy for a guy like Stann to walk away from this sport. It means more to him than just paychecks and career opportunities, and it has ever since he got into it during his time in the Marine Corps, when he was unconsciously looking for some physical and psychological escape between deployments to Iraq.

“That was really what spawned my mixed martial arts career. It was really like therapy for me, though I didn’t realize it at the time. After my first deployment, the first thing I did was send emails to [fight promoters] Scott Adams and Matt Lindland, basically cursing at them because they’d sent me rejection emails when I’d tried to get on a card.

“Then Matt Lindland booked me for a fight, and that was all I wanted to do every time I got back from war. It was my sanctuary. It’s where I went to forget about everything else.”

Now he’s walking away from it, and sure, Stann said, it stings a bit. Just this past weekend, he was at UFC 162 in Las Vegas, and “I was watching thinking about how I would love to still be able to walk down that tunnel and go out there and compete, and I still think I’m capable of doing it.”

He just doesn’t think it’s worth it for him anymore, nor does he think it would be the best thing for his family. Really, that’s what it comes down to. He had the same pangs of nostalgia and dim regret after he left the Marine Corps, he said, but he left it for very similar reasons. He couldn’t justify the time spent away from his wife, his young daughters, all the people who needed him back home. So he left the Marines, even though he loved it. Sometimes he goes back now to speak at various military bases.

“Every time I go, I miss it,” Stann said. “I start to wonder if I could have been a general. I wonder if I could have been on the Joint Chiefs of Staff. I wonder about all the things I’ve missed. That does come to mind, but when I look back on my decision I know it absolutely was the right decision for my family. And at the end of the day, my goal in life is to provide for my family and spend as much time with them as I can. That’s it.

“After seeing as much life taken as I have, and then, with my wife, seeing it given, there’s no doubt in my mind that the purpose of my life, at least, is to be a father and husband. Everything else I do is basically a puppet show and a means to an end. And when you’re preparing for a fight, so much of your mind is occupied by it. Even when you’re not training, you’re still thinking about that fight. It’s hard to devote the time to my family, or to the other things I’m doing, or to educating myself for future things I want to do with my life. That tells me that it’s time. It’s time now.”